linux/fs/udf/unicode.c
Andrew Gabbasov 484a10f493 udf: Merge linux specific translation into CS0 conversion function
Current implementation of udf_translate_to_linux function does not
support multi-bytes characters at all: it counts bytes while calculating
extension length, when inserting CRC inside the name it doesn't
take into account inter-character boundaries and can break into
the middle of the character.

The most efficient way to properly support multi-bytes characters is
merging of translation operations directly into conversion function.
This can help to avoid extra passes along the string or parsing
the multi-bytes character back into unicode to find out it's length.

Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2016-02-09 13:05:23 +01:00

385 lines
8.6 KiB
C

/*
* unicode.c
*
* PURPOSE
* Routines for converting between UTF-8 and OSTA Compressed Unicode.
* Also handles filename mangling
*
* DESCRIPTION
* OSTA Compressed Unicode is explained in the OSTA UDF specification.
* http://www.osta.org/
* UTF-8 is explained in the IETF RFC XXXX.
* ftp://ftp.internic.net/rfc/rfcxxxx.txt
*
* COPYRIGHT
* This file is distributed under the terms of the GNU General Public
* License (GPL). Copies of the GPL can be obtained from:
* ftp://prep.ai.mit.edu/pub/gnu/GPL
* Each contributing author retains all rights to their own work.
*/
#include "udfdecl.h"
#include <linux/kernel.h>
#include <linux/string.h> /* for memset */
#include <linux/nls.h>
#include <linux/crc-itu-t.h>
#include <linux/slab.h>
#include "udf_sb.h"
static int udf_uni2char_utf8(wchar_t uni,
unsigned char *out,
int boundlen)
{
int u_len = 0;
if (boundlen <= 0)
return -ENAMETOOLONG;
if (uni < 0x80) {
out[u_len++] = (unsigned char)uni;
} else if (uni < 0x800) {
if (boundlen < 2)
return -ENAMETOOLONG;
out[u_len++] = (unsigned char)(0xc0 | (uni >> 6));
out[u_len++] = (unsigned char)(0x80 | (uni & 0x3f));
} else {
if (boundlen < 3)
return -ENAMETOOLONG;
out[u_len++] = (unsigned char)(0xe0 | (uni >> 12));
out[u_len++] = (unsigned char)(0x80 | ((uni >> 6) & 0x3f));
out[u_len++] = (unsigned char)(0x80 | (uni & 0x3f));
}
return u_len;
}
static int udf_char2uni_utf8(const unsigned char *in,
int boundlen,
wchar_t *uni)
{
unsigned int utf_char;
unsigned char c;
int utf_cnt, u_len;
utf_char = 0;
utf_cnt = 0;
for (u_len = 0; u_len < boundlen;) {
c = in[u_len++];
/* Complete a multi-byte UTF-8 character */
if (utf_cnt) {
utf_char = (utf_char << 6) | (c & 0x3f);
if (--utf_cnt)
continue;
} else {
/* Check for a multi-byte UTF-8 character */
if (c & 0x80) {
/* Start a multi-byte UTF-8 character */
if ((c & 0xe0) == 0xc0) {
utf_char = c & 0x1f;
utf_cnt = 1;
} else if ((c & 0xf0) == 0xe0) {
utf_char = c & 0x0f;
utf_cnt = 2;
} else if ((c & 0xf8) == 0xf0) {
utf_char = c & 0x07;
utf_cnt = 3;
} else if ((c & 0xfc) == 0xf8) {
utf_char = c & 0x03;
utf_cnt = 4;
} else if ((c & 0xfe) == 0xfc) {
utf_char = c & 0x01;
utf_cnt = 5;
} else {
utf_cnt = -1;
break;
}
continue;
} else {
/* Single byte UTF-8 character (most common) */
utf_char = c;
}
}
*uni = utf_char;
break;
}
if (utf_cnt) {
*uni = '?';
return -EINVAL;
}
return u_len;
}
#define ILLEGAL_CHAR_MARK '_'
#define EXT_MARK '.'
#define CRC_MARK '#'
#define EXT_SIZE 5
/* Number of chars we need to store generated CRC to make filename unique */
#define CRC_LEN 5
static int udf_name_conv_char(uint8_t *str_o, int str_o_max_len,
int *str_o_idx,
const uint8_t *str_i, int str_i_max_len,
int *str_i_idx,
int u_ch, int *needsCRC,
int (*conv_f)(wchar_t, unsigned char *, int),
int translate)
{
uint32_t c;
int illChar = 0;
int len, gotch = 0;
for (; (!gotch) && (*str_i_idx < str_i_max_len); *str_i_idx += u_ch) {
if (*str_o_idx >= str_o_max_len) {
*needsCRC = 1;
return gotch;
}
/* Expand OSTA compressed Unicode to Unicode */
c = str_i[*str_i_idx];
if (u_ch > 1)
c = (c << 8) | str_i[*str_i_idx + 1];
if (translate && (c == '/' || c == 0))
illChar = 1;
else if (illChar)
break;
else
gotch = 1;
}
if (illChar) {
*needsCRC = 1;
c = ILLEGAL_CHAR_MARK;
gotch = 1;
}
if (gotch) {
len = conv_f(c, &str_o[*str_o_idx], str_o_max_len - *str_o_idx);
/* Valid character? */
if (len >= 0)
*str_o_idx += len;
else if (len == -ENAMETOOLONG) {
*needsCRC = 1;
gotch = 0;
} else {
str_o[(*str_o_idx)++] = '?';
*needsCRC = 1;
}
}
return gotch;
}
static int udf_name_from_CS0(uint8_t *str_o, int str_max_len,
const uint8_t *ocu, int ocu_len,
int (*conv_f)(wchar_t, unsigned char *, int),
int translate)
{
uint32_t c;
uint8_t cmp_id;
int idx, len;
int u_ch;
int needsCRC = 0;
int ext_i_len, ext_max_len;
int str_o_len = 0; /* Length of resulting output */
int ext_o_len = 0; /* Extension output length */
int ext_crc_len = 0; /* Extension output length if used with CRC */
int i_ext = -1; /* Extension position in input buffer */
int o_crc = 0; /* Rightmost possible output pos for CRC+ext */
unsigned short valueCRC;
uint8_t ext[EXT_SIZE * NLS_MAX_CHARSET_SIZE + 1];
uint8_t crc[CRC_LEN];
if (str_max_len <= 0)
return 0;
if (ocu_len == 0) {
memset(str_o, 0, str_max_len);
return 0;
}
cmp_id = ocu[0];
if (cmp_id != 8 && cmp_id != 16) {
memset(str_o, 0, str_max_len);
pr_err("unknown compression code (%d)\n", cmp_id);
return -EINVAL;
}
u_ch = cmp_id >> 3;
ocu++;
ocu_len--;
if (ocu_len % u_ch) {
pr_err("incorrect filename length (%d)\n", ocu_len + 1);
return -EINVAL;
}
if (translate) {
/* Look for extension */
for (idx = ocu_len - u_ch, ext_i_len = 0;
(idx >= 0) && (ext_i_len < EXT_SIZE);
idx -= u_ch, ext_i_len++) {
c = ocu[idx];
if (u_ch > 1)
c = (c << 8) | ocu[idx + 1];
if (c == EXT_MARK) {
if (ext_i_len)
i_ext = idx;
break;
}
}
if (i_ext >= 0) {
/* Convert extension */
ext_max_len = min_t(int, sizeof(ext), str_max_len);
ext[ext_o_len++] = EXT_MARK;
idx = i_ext + u_ch;
while (udf_name_conv_char(ext, ext_max_len, &ext_o_len,
ocu, ocu_len, &idx,
u_ch, &needsCRC,
conv_f, translate)) {
if ((ext_o_len + CRC_LEN) < str_max_len)
ext_crc_len = ext_o_len;
}
}
}
idx = 0;
while (1) {
if (translate && (idx == i_ext)) {
if (str_o_len > (str_max_len - ext_o_len))
needsCRC = 1;
break;
}
if (!udf_name_conv_char(str_o, str_max_len, &str_o_len,
ocu, ocu_len, &idx,
u_ch, &needsCRC, conv_f, translate))
break;
if (translate &&
(str_o_len <= (str_max_len - ext_o_len - CRC_LEN)))
o_crc = str_o_len;
}
if (translate) {
if (str_o_len <= 2 && str_o[0] == '.' &&
(str_o_len == 1 || str_o[1] == '.'))
needsCRC = 1;
if (needsCRC) {
str_o_len = o_crc;
valueCRC = crc_itu_t(0, ocu, ocu_len);
crc[0] = CRC_MARK;
crc[1] = hex_asc_upper_hi(valueCRC >> 8);
crc[2] = hex_asc_upper_lo(valueCRC >> 8);
crc[3] = hex_asc_upper_hi(valueCRC);
crc[4] = hex_asc_upper_lo(valueCRC);
len = min_t(int, CRC_LEN, str_max_len - str_o_len);
memcpy(&str_o[str_o_len], crc, len);
str_o_len += len;
ext_o_len = ext_crc_len;
}
if (ext_o_len > 0) {
memcpy(&str_o[str_o_len], ext, ext_o_len);
str_o_len += ext_o_len;
}
}
return str_o_len;
}
static int udf_name_to_CS0(uint8_t *ocu, int ocu_max_len,
const uint8_t *str_i, int str_len,
int (*conv_f)(const unsigned char *, int, wchar_t *))
{
int i, len;
unsigned int max_val;
wchar_t uni_char;
int u_len, u_ch;
if (ocu_max_len <= 0)
return 0;
memset(ocu, 0, ocu_max_len);
ocu[0] = 8;
max_val = 0xff;
u_ch = 1;
try_again:
u_len = 1;
for (i = 0; i < str_len; i++) {
/* Name didn't fit? */
if (u_len + u_ch > ocu_max_len)
return 0;
len = conv_f(&str_i[i], str_len - i, &uni_char);
if (!len)
continue;
/* Invalid character, deal with it */
if (len < 0) {
len = 1;
uni_char = '?';
}
if (uni_char > max_val) {
max_val = 0xffff;
ocu[0] = 0x10;
u_ch = 2;
goto try_again;
}
if (max_val == 0xffff)
ocu[u_len++] = (uint8_t)(uni_char >> 8);
ocu[u_len++] = (uint8_t)(uni_char & 0xff);
i += len - 1;
}
return u_len;
}
int udf_CS0toUTF8(uint8_t *utf_o, int o_len, const uint8_t *ocu_i, int i_len)
{
return udf_name_from_CS0(utf_o, o_len, ocu_i, i_len,
udf_uni2char_utf8, 0);
}
int udf_get_filename(struct super_block *sb, const uint8_t *sname, int slen,
uint8_t *dname, int dlen)
{
int (*conv_f)(wchar_t, unsigned char *, int);
int ret;
if (!slen)
return -EIO;
if (dlen <= 0)
return 0;
if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
conv_f = udf_uni2char_utf8;
} else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
conv_f = UDF_SB(sb)->s_nls_map->uni2char;
} else
BUG();
ret = udf_name_from_CS0(dname, dlen, sname, slen, conv_f, 1);
/* Zero length filename isn't valid... */
if (ret == 0)
ret = -EINVAL;
return ret;
}
int udf_put_filename(struct super_block *sb, const uint8_t *sname, int slen,
uint8_t *dname, int dlen)
{
int (*conv_f)(const unsigned char *, int, wchar_t *);
if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {
conv_f = udf_char2uni_utf8;
} else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {
conv_f = UDF_SB(sb)->s_nls_map->char2uni;
} else
BUG();
return udf_name_to_CS0(dname, dlen, sname, slen, conv_f);
}